1. Field of the Invention
The present invention relates to a display apparatus including a display panel whose height can be adjusted through a height adjusting device.
2. General Background
Display apparatuses are used in many types of equipment, such as personal computers, navigation systems, notebooks, and so on. In order to provide a better viewing angle for users, a height adjustable function for a display apparatus used with a personal computer is desired.
Referring to FIG. 8 and FIG. 9, a typical display apparatus 1 includes a base 11, a support 12, and a display panel 13. The support 12 is fixed on the base 11, and supports the display panel 13. The stand 13 can adjust a height of the display panel 13 relative to the base 11. The base 11 is substantially disc-shaped, and is positioned on a horizontal surface (not shown) to maintain the stability of the display apparatus 1.
The support 12 includes a tubular body 121, a compression spring 123, a slider 125, a magnet set 127, a ring 129, and a nut 130. The tubular body 121 is located at a center portion (not labeled) of the base 11, and defines an accommodating space therein. The compression spring 123 is accommodated in the accommodating space of the tubular body 121. The slider 125 is fixed at one end of the compression spring 123, and is also accommodated in the accommodating space of the tubular body 121. The ring 129 is fitted around the tubular body 121, and can be moved up or down along the tubular body 121. Two parts of the magnet set 127 are disposed in the slider 125 and the ring 129 respectively, and are spaced by a wall (not labeled) of the tubular body 121. The nut 130 covers a top opening of the tubular body 121, so as to prevent the compression spring 123 and the slider 125 from sliding out from the tubular body 121.
The display panel 13 is configured to display, e.g., images or videos. The display panel 13 is fixed to the ring 129 through bolts (not labeled), and can be moved up and down with the ring 129 along the tubular body 121.
The operation principle of the display apparatus 1 is as follows. Because the two parts of the magnet set 127 are attractive to each other and are disposed in the slider 125 and the ring 129 respectively, the slider 125 and the ring 129 clamp the wall of the tubular body 121 due to an attraction force between the two parts of the magnet set 127. Friction forces are generated, between the slider 125 and the wall of the tubular body 121 and between the ring 129 and the wall of the tubular body 121. At the same time, the compression spring 123 generates an elastic force to support the slider 125 and push the slider 125 upward. By adjusting the elastic force and the friction forces, the elastic force, the friction forces, and gravity acting on the display panel 13 can cooperatively keep the display panel 13 steady at a desired height.
When lifting the display panel 13, an upward external force is applied to the display panel 13. If a sum of the external force and the elastic force is greater than a sum of the friction forces and the force of gravity, the display panel 13 can be lifted to a higher position. When the external force is removed, the display panel 13 stays at the higher position because directions of the friction forces are reversed. When lowering the display panel 13, a downward external force is applied to the display panel 13. If a sum of the external force and the force of gravity is greater than a sum of the elastic force and the friction forces, the display panel 13 can be lowered to a lower position. When the external force is removed, the display panel stays at the lower position because directions of the friction forces are reversed.
However, in order to achieve the height adjustable function of the display panel 13, the display apparatus 1 needs the magnet set 127 to generate the friction forces. Therefore the display apparatus 1 has a rather complicated structure. In addition, a process of adjustment and calibration of the magnet set 127 is needed in order to achieve suitable attraction force. This makes a process of fabricating the display apparatus 1 somewhat complicated.
Therefore, a new display apparatus that can overcome the above-described problems is desired.